Can food be a drug?

Worldwide obesity is on the rise. Although its negative influence on our health has already been proven many times, the number of people affected by obesity is steadily increasing. Why do people gain weight and why is it so difficult for many of us to lose the excess weight? Neuroscientists and psychologists have investigated this very question while looking for the causes of obesity. They examined the influence of high-calorie, high-sugar and high-fat diets on the brain, as well as their influence on behavior, and compared them with other drugs.

The characteristics of addiction are defined as loss of control, tolerance and withdrawal symptoms. Those affected consume substances in an uncontrolled manner and must increase their dosage in order to achieve the desired effect, as they develop a tolerance over the course of their addiction. At the same time, stopping the intake results in serious physical and mental withdrawal symptoms. The fifth edition of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-5), which is used to diagnose and classify mental illnesses, defines eleven symptoms that constitute substance abuse. The diagnosis can also be made without the presence of the already mentioned symptoms.

Animal experiments have revealed a correlation between high-calorie food products and drugs. Both food and drugs act in a similar way by activating the brain's reward center and other neuronal circuits, releasing the agent substance dopamine, which is related to feelings of happiness, joy and contentment. In addition, sugar dependence was induced under experimental conditions and withdrawal symptoms were observed. However, the transferability of these animal experiments to humans is still being investigated. With the exception of caffeine, no definite tolerance development or withdrawal symptoms have yet been demonstrated in humans through food.

On the other hand, considering the DSM-5 criteria, many people's eating habits regarding sweets, chips, and fast food show characteristics of mild to moderate substance addiction. These characteristics include a recurrent craving, as well as the consumption of larger food portions than originally intended. Repeated failed attempts at moderation are part of this cycle, as well as a continuation of the habit, especially when it has already lead to negative consequences.

In a few cases, eating behaviors have met the criteria of serious addiction. During so-called ‘binge eating’, people lose control over their eating habits and consume enormous amounts of food in a very short time. Over time, a complete addiction can develop, along with serious negative impacts on people’s private and professional lives. In contrast to substance abuse, however, binge eating is an eating disorder. Although there are parallels between the effects of certain foods and addictive substances, sugar and fat can not be equated with cocaine or heroin. Especially since they influence the brain to a far lesser degree. While the existence of addictive eating behaviors is undisputed, only a fraction of overweight people have an evident food addiction. Still, the findings provide important foundations for possible pathomechanisms of obesity and could be of future therapeutic relevance.